I suggest you ...

Start a game from a position of replay

it isn't a rare thing when two wormers have a row because of positions. "You had better luck, you had better position" etcetc and it mightbe true when 3 of opponent can be sinked and the oppoent doesnt have any. This would be a VERY good option to start a new game from an old replay's position and the two players can change the colors (with the same map/terrarium of course). This would be also a great challenge, when two more skilled player wants to try these positions

I feel this feature should be integrated with “Allow resuming an on-line match using the replay file”. Part of that feature would involve choosing which frame to start from, and in this case it’d be frame 0. (In the full-featured version of the feature, the difference between this kind of resumption and “secure resumption from a disconnected game at the point of disconnection” would be made obvious to all players before the game started.)

Having said that, it is possible to do this right now with no modification to W:A (and has been since before the betas). I don’t think I should reveal the method here; if used dishonorably, it could give the host quite an unfair advantage. (In fact, I plan to make it impossible once the resumption feature is implemented.)

Not really FFie :), worms won't be placed in the exact same way, one pixel makes the difference in a grassy surface. Also the mines and oil drums placement will be different. Would be indeed interesting to have the chance of switching places with your opponent for all the random placement schemes.
Could it be possible that when you extract the map, the worms and objects placement is not lost?